LEIGH SALES, PRESENTER: She was once North Korea's top female secret agent, a woman who successfully carried out a mission to blow up a South Korean airliner.
In 1987, Kim Hyon Hui planted the bomb that left 115 people dead, but she was later caught. After trying to kill herself with poison, Kim Hyon Hui was given the death sentence.
A few years later, she was later pardoned, and she now lives in the South at an undisclosed location surrounded by bodyguards.
As North Korea warns it will launch another missile test, the former super spy sat down for an exclusive interview with the ABC's North Asia correspondent Mark Willacy.
MARK WILLACY, REPORTER: Revolutionary, assassin, spy - Kim Hyon Hui has been all of those things. But she'll be forever infamous as one of the North Korea's most daring and destructive secret agents, the femme fatale behind the rogue state's most deadly terrorist act.
KIM HYON HUI, FORMER NORTH KOREAN SPY (voiceover translation): It was a huge operation and I was trained to get the operation done. As an agent in North Korea, I was in no position to argue if a mission was right or wrong. I was trained to carry out the mission even if it cost people's lives.
MARK WILLACY: Kim Hyun Hee's mission was to bomb a South Korean airliner. The attack in 1987 killed all 115 people on board and led to the United States listing North Korea as a state sponsor of terrorism.
KIM HYON HUI (voiceover translation): From the moment I got on the Korean air flight, left the bomb in the overhead locker and until I got off, I was nervous, every second of the operation.
MARK WILLACY: Kim Hyon Hui sat down in Seoul for an exclusive interview with 7.30.
With tensions on the Peninsula higher than they've been in years, her story offers a glimpse inside one of the world's most unpredictable and secretive states, a regime founded by the eternal leader Kim Il-sung.
KIM HYON HUI (voiceover translation): In North Korea I was taught that our leader Kim Il-sung was a god. You were taught to put him before your own parents. You learned from early childhood to say "Thank you, great leader" for everything. And if you said the wrong thing, even if it was a slip of the tongue, you'd end up in the gulag. North Korea is not a state, it's a cult.
MARK WILLACY: In 1970s North Korea, in the Orwellian uniformity of this cult, Kim Hyon Hui stood out, and the regime quickly noticed the teenager because of her sharp intelligence and stunning beauty. That plus her ability to speak perfect Japanese meant Kim Hyon Hui was singled out to become a spy.
KIM HYON HUI (voiceover translation): One day a black sedan showed up at my school. They were from the central party and told me I'd been chosen. I wasn't even allowed time to say goodbye to my friends; I was just told to pack. I was given one last night with my family.
MARK WILLACY: In 1980, Kim Hyon Hui was sent to North Korea's elite spy training school in the remote mountains. She was given a new name and intensive training in martial arts, weapons and languages. After nearly eight years of learning spycraft, Kim was ready for her defining mission, one devised by the son of the founder and the country's future "Dear Leader".
KIM HYON HUI (voiceover translation): In North Korea, you needed Kim Jong-il's approval for the most minor thing, let alone a spy mission. He personally ordered the operation to bomb the Korean air flight.
MARK WILLACY: This was the ultimate target of Kim Hyon Hui's mission, the 1988 Seoul Olympics.
NEWSREADER (archive footage): These games are the first in 12 years with no major boycotts and the Eastern Bloc, led by the Soviet Union, is expected to dominate the medals.
MARK WILLACY: The future "Dear Leader" of North Korea, Kim Jong-il hoped the bombing of Flight 858 would scare foreign teams into staying away from the Olympics
NEWSREADER (archive footage): The Australians were amongst the brightest in the stadium in gold stockman's coats and wide-brimmed hats.
MARK WILLACY: Flight 858 was scheduled to take off from Baghdad on 28th November, 1987, bound for Seoul. But it would not reach its destination.
Kim Hyon Hui was teamed up with a legendary North Korean spy Kim Sung-il. Together, they flew from Pyongyang to Moscow. Then they travelled to Budapest where they were given fake Japanese passports and began posing a father and daughter touring Europe together. From Budapest, they flew to Vienna, then to Belgrade.
KIM HYON HUI (voiceover translation): My partner and I had experience as agents in Europe. We were confident there and knew how the airports worked.
MARK WILLACY: But they were soon flying out for unfamiliar territory to Baghdad. There, Kim Hyon Hui set the timer on the bomb, which was hidden inside a transistor radio. It was set to explode nine hours after flight 858 took off, as the plane was in the air en route to Seoul.
KIM HYON HUI (voiceover translation): It was such a huge operation. I was so focused on trying to complete it. I was worried if I could do it.
MARK WILLACY: After stowing the bomb, the two North Koreans left the plane during a stopover in Abu Dhabi and made their way to Bahrain. Flight 858, meanwhile, had continued on towards Seoul. But over the Andaman Sea, the timer stopped ticking.
In Seoul, the relatives of the 115 people on board were told the plane had gone down, with suspicions immediately focusing on a bomb.
Back in Bahrain, 25-year-old agent Kim Hyon Hui was desperately trying to make her escape.
KIM HYON HUI (voiceover translation): We had nowhere to run. We had to get out of Bahrain, but our next plane didn't leave for two days. I was so anxious; it was driving me crazy. I had no idea if we'd been successful or if the plane had been blown up.
NEWSREADER (archive footage): With the search for wreckage of the Korean airliner concentrated on the Thai-Burma border, a strong suspicion has developed it was the target of a terrorist bomb.
MARK WILLACY: But their mission was about to unravel. Two days later, as they were about to board a plane to get out of Bahrain, Kim Hyon Hui and her partner were suddenly confronted by authorities who discovered they were travelling on fake passports.
KIM HYON HUI (voiceover translation): We were told that flight 585 had exploded and that there were no survivors. We knew then our bombing operation had been successful.
MARK WILLACY: As they were being searched, the veteran agent Kim Sung-il told his young comrade it was time to bite down on an ampoule of cyanide hidden in their cigarettes.
KIM HYON HUI (voiceover translation): He said, "What awaits us is interrogation and eventually death. I have lived a long time and I am an old man, but you are so young. I am sorry." I knew when an operation failed, an agent had to kill themselves, so I bit down on the cyanide ampoule. As I did, I remembered my mother in North Korea, then I blacked out.
MARK WILLACY: The older agent died almost immediately. But Kim Hyon Hui was revived. And after recovering, she was flown to South Korea to stand trial. There, she refused to break and admit her role in the bombing for many days, but the interrogators slowly ground her down.
KIM HYON HUI (voiceover translation): For the first eight days, I kept resisting with lies, but then my interrogators took me for drives through Seoul and I saw how modern it was and I listened to how the agents around me spoke so freely. This contradicted everything I'd been told in North Korea. I realised then I'd taken innocent lives and I expected to be given the death penalty.
MARK WILLACY: And that's what happened. But unlike her victims on flight 858, Kim Hyon Hui would be spared death. She was pardoned, with the South Korean Government deciding she was merely a brainwashed victim of the Kim cult. Today she lives in South Korea at an undisclosed location, surrounded at all times by half a dozen bodyguards, fearful North Korean assassins may strike at any time.
KIM HYON HUI (voiceover translation): I deserved the death penalty for what I did, but I believe my life was spared because I was the only witness to this terror perpetrated by North Korea. As the only witness, it is my destiny to testify about the truth.
MARK WILLACY: But recently, the threats from the North have been targeted at the whole of the South Korea. Not to mention US bases in Guam, Japan, Hawaii and the continental United States.
This former North Korean agent believes the regime's young untested leader is trying to tighten his grip on power by playing the tough guy in front of his domestic audience.
KIM HYON HUI (voiceover translation): Kim Jong-un is too young and too inexperienced. He's struggling to gain complete control over the military and to win their loyalty. That's why he's doing so many visits to military bases, to firm up support. He's also using the nuclear program as a bargaining chip for aid, to keep the public behind him.
MARK WILLACY: To Kim Hyon Hui, the fact that a third-generation of the Kim dynasty is threatening the world is horrifying. But she knows those suffering the most are the millions doomed to live, work and die under the heel of the regime, including the family she had to leave behind.
KIM HYON HUI (voiceover translation): I once heard a story that a defector saw my family in a concentration camp about 15 years ago. But to this day, I have no idea what happened to my family.
MARK WILLACY: Kim Hyon Hui wasn't so much chosen as compelled by the North Korean regime to carry out a horrific crime, one that shattered so many lives and one that haunts her every day of her life.
KIM HYON HUI (voiceover translation): I regret what I did and I am repentant. I feel I should not hide the truth from the family members of those who died. It is my duty to tell them what happened.
LEIGHSALES: Mark Willacy with that amazing repo